Beginning with a new, second OS X 10.8.3 beta build, Apple is now giving developers the option of obtaining beta OS updates through the Mac App Store's Software Update mechanism. The move should make distribution of updates to registered testing devices more uniform, and expands the use of "developer channel" updates available through the store. Apple says that while email notification of new updates will continue as well, a new tool installed by registered developers will allow Software Update to notify users of new builds.

The latest build of 10.8.3, with build number 12D38 (six builds further along than last week's 12D32), adds Safari to the items that developers should focus on. The previous build required attention to AirPlay, Game Center, AirPort and Core Graphics. Known issues listed include problems with graphics on waking from sleep, and VNC remote control issues.
No release date has been given for 10.8.3, but it is worth nothing that the current release, v10.8.2, had five beta releases before it was finally released in September.